Pulleys such as drive pulleys (both front-side and back-side), idler pulleys, tensioner pulleys, and the like are frequently employed for automotive use, e.g. to drive or tension a belt of a drive system. The belt drive system can be accomplished by using a driver pulley and one or more idler pulleys and a belt trained around the belt surface of each of the various pulleys. The belt surface may be, for example, smooth, deep V-shaped, cogged or multi-ribbed.
In such automotive and other industrial applications, contaminants such as dust, sand, salt, and/or other foreign matter can find a way into the pulley's bearing. Bearings wear more quickly when left open to contaminants, thereby reducing the lifespan of the bearing. Contaminants can also cause the ball or rolling element to seize up, which is a serious problem. Seizing can cause the driving belt to break as a result of the belt sliding on a locked pulley.
A bearing seal is a first line of defense against contaminants, but is often not enough. Various sealing rings or covers to reduce the amount of dirt and other contaminants like those described in U.S. Pat. No. 3,537,725, U.S. Pat. No. 4,113,328, and U.S. Pat. No. 7,011,593 have been attempted. Some bearing caps have been designed to attach directly to the pulley or pulley body, for example the snap-on bearing cap described in U.S. Pat. No. 4,793,457 and the flanged bearing cap grooved bearing cap retainer combination described in U.S. Published Patent Application 2007/0072714. The aforementioned pulley-bearing cap designs are not ideal, especially for injection molded pulley assemblies.
Injection molding is a well-known technique for forming pulley assemblies. However, the molds place limits on the complexity of the pulley body's design. Particularly, complex features for attaching a bearing cap to the pulley body, for example snap-fit configurations, are difficult to achieve due to the complexity of the under cuts required to form such features within the mold.
Accordingly, a new design for retaining a bearing cap on a pulley is needed that does not increase the complexity of the pulley body's design and accordingly the design of the mold used to form the pulley body.